During the November 19th EVA, the crew members reported that the Extravehicular Mobility Unit’s (EMU or EVA suit) integrated thermal meteoroid garments were severely worn by the abrasive nature of the lunar dust. During the ascent to lunar orbit, the dust that was tracked into the Lunar Excursion Module became weightless, causing the crew members to experience difficulty breathing and requiring them to put on their helmets.

While egressing the Lunar Excursion Module (LEM), one of the crew members experienced difficulty crawling through the hatch due to tight clearances between the LEM hatch and the Portable Life Support System attached to the back of the suit.

During preparation for the September 13th EVA, the crew member that would be performing the spacewalk became overheated in the suit prior to egressing the capsule. Difficulty attaching the helmet visor contributed to the exertion and overheating. Because the life support oxygen cooling system heat exchanger could only operate in a vacuum, the crew member was not able to receive cooling from it. The EVA proceeded, but the crew member that remained in the capsule during the EVA brought the spacewalking crew member in early, noting that the crew member was sweating and not able to see well.

While moving over to the Agena docking target, the EVA crew member dislodged a sharp-edged electrical discharge ring that had the potential to damage the suit or its umbilical. After returning to the Gemini capsule, the EVA umbilical blocked one of the crew members from seeing the control panel, preventing the crew member from reporting the status of fuel to ground control. The difficulty that the crew members had with the umbilical also led to the radio accidentally being shut off for a brief time.

EVA terminated early due to eye irritations from lithium hydroxide being blown into helmet when suit fans were run simultaneously.

While executing the July 19th EVA, the crew member conducting the spacewalk experienced eye irritations causing the EVA to be terminated early. The cause of the irritation was traced to lithium hydroxide used for carbon dioxide absorption leaking into the helmet when both suit fans were operating simultaneously.

During the June 5th EVA, the crew member conducting the spacewalk experienced difficulty maneuvering around the outside of the capsule. While moving around during the EVA, the crew member’s suit became damaged, resulting in the crew member having thermal burns on his back from the sunlight striking the torn areas of the suit. The workload that the crew member experienced also exceeded the cooling capacity of the suit.

On June 3rd 1965 the crew of Gemini 4 experienced difficulty closing the capsule hatch after completion of the EVA. The crew was finally able to get the hatch closed when one crew member pulled on the other crew member while turning the hatch handle. While struggling to close the hatch, the crew member performing the spacewalk exerted himself beyond the cooling capacity of the suit, leading to slight fogging of the helmet visor.

During the March 18th 1965 EVA, the spacesuit the crew member was wearing while performing the EVA ballooned, causing an increase in the suit’s stiffness. After completing the EVA, the crew member entered the airlock head first and discovered that the suit would not bend enough to allow him to turn around and close the hatch. The crew member was forced to lower the pressure inside the suit, risking the potential onset of dysbarism (“the bends”). The struggle to enter and seal the airlock led to the crew member overheating, nearly to the point of heatstroke, due to the workload exceeding the cooling capacity of the early EVA suit.

After performing the EVA on August 15th, one of the crew members noticed a small puncture in the suit’s pressure bladder. The cause of the puncture was possibly a sharp wire on the KRT-10 antenna that the crew members removed from the Salyut 6 station.

On December 20th while performing an EVA from the Salyut 6 docking port, one crew member partially left the docking port without attaching the safety tether. While the crew member was untethered, the suit umbilical was still attached and prevented him from accidentally floating free of the station.

While performing the February 3rd EVA, one crew member’s suit cooling system developed a leak similar to the one experienced on EVA 2. The crew member switched to minimum cooling, minimizing the amount of cooling water leaking, and completed the tasks assigned for the EVA. A later investigation determined that the probable cause of the leaking was due to the connectors being exposed to the cold environment of space and a small side load being placed on the connector.

During the December 29th EVA, a cooling water leak caused ice to form on the front of one crew member’s suit. A later investigation determined that the probable cause of the leaking was due to the connectors being exposed to the cold environment of space and a small side load being placed on the connector.

During the December 25th EVA, a cooling water leak caused yellow ice to form on the front of one crew member’s belly-mounted pressure control unit. The color of the ice indicated that the leak was from one of the two water connectors (quick disconnects) of the composite connector at the interface of the life support umbilical/pressure control unit. The leak was too small to fully deplete the cooling water supply. A spare unit was used on subsequent EVAs. A later investigation determined that the probable cause of the leaking was due to the connectors being exposed to the cold environment of space and a small side load being placed on the connector.

During the November 22nd EVA, the crew members experienced difficulty keeping their suit umbilicals separated. This cost them time and effort to keep the umbilicals under control and could have presented a risk of severe entanglement.

During the September 22nd EVA, the airlock module suit cooling system suffered leaks and was inoperable for the EVA. The physically undemanding nature of the tasks to be completed allowed the EVA to proceed with only air cooling.

Primary EVA heat exchanger module suffered minor clogging during the EVA, leading engineers to design a new module to serve as a backup.

During the June 7th EVA, the Skylab primary EVA heat exchanger module suffered from minor clogging, but the EVA was able to continue. The clogging of the heat exchanger led engineers to design a new module that would serve as a backup. The new backup module was delivered to Skylab in July 1973 by the next crew.

One LRV fender broke off, which resulted in the crew getting showered by dust while driving.

During the December 11th EVA, one of the crew members suffered contusions to his hand while extracting a core sample. The device used to obtain the core samples became stuck, despite a design that was supposed to ease removal of the core sample. During the EVA, part of the Lunar Rover fender was broken off, but taped back in position. On the way to the first geological survey station the “repaired” fender fell off and showered the crew members with dust.

During the EVA on April 23rd, the Lunar Rover suffered a temporary navigational computer failure. The crew members used the sun’s position to determine their location, allowing them to locate the Lunar Excursion Module. An investigation later revealed that the most probable cause of the issues with the navigation system was improper wire crimps on the flight vehicle when compared with the solder connections used in the test vehicle on the ground. The improper crimps allowed the wires to loosen when exposed to cold temperatures, causing loose connections.

During the EVA on April 22nd one crew member’s Portable Life Support System radio antenna struck the Lunar Excursion Module’s hatch frame, breaking off a portion of the antenna. The damage to the antenna caused a small drop in signal strength, but the EVA was allowed to continue.

During the April 21st EVA, one of the crew members tripped over the heat flow sensor cable connected to the Apollo Lunar Surface Experiments Package (ALSEP), tearing it loose. Mission control elected not to repair the cable on the subsequent EVA due to concern that the repair would take too much time and could possibly short-circuit the ALSEP.

One of the crew members attempted to jump and salute the flag they had placed, but slipped and fell onto the Portable Life Support System (PLSS). However, no significant damage was done to the PLSS, which remained operational.

After ingressing the Lunar Excursion Module, the crew members reported the same problems that previous flights had with the lunar dust – stuck zippers and disconnects, and scratched indicators that were difficult to read.

During the August 1st EVA, the vertical Portable Life Support System (PLSS) radio antenna snapped off of one crew member’s PLSS. The other crew member taped it back into a horizontal position. While navigating back to the Lunar Excursion Module (LEM), the crew members experienced difficulty navigating until they encountered their outbound tracks, which led them back to the LEM. An investigation later revealed that the most probable cause of the issues with the navigation system was improper wire crimps on the flight vehicle when compared with the solder connections used in the test vehicle on the ground. The improper crimps allowed the wires to loosen when exposed to cold temperatures, causing loose connections.

During the July 31st EVA, while driving the Lunar Roving Vehicle, the front steering failed. The crew member driving was able to steer the rover with only the rear steering. Also during the EVA, one of the crew members’ drink bags failed to operate, causing the crew member to become dehydrated. After completing the EVA, the crew members discovered that the abrasive lunar dust made the Portable Life Support System (PLSS) connectors tight and difficult to operate. In addition, the crew members also experienced pain in their fingers caused by their fingernails pressing against their glove fingertips.

During the April 11th EVA, the Russian Orlan-DM spacesuit in use by one of the crew members experienced a minor pressure drop. The cause of the pressure drop was quickly determined to be an incorrect switch position, which was corrected, allowing the EVA to continue.

Difficulty in handling satellite due to lack of visual cues between EVA astronauts.

Accidentally reused lithium hydroxide canisters from first EVA.

During the September 1st EVA when the EVA crew members were handling a satellite from opposite sides, a lack of sight between them hindered visual cues and posed a potential threat of collision with Space Shuttle Discovery. The lack of visual cues caused the EVA crew members to impart opposite motions into the satellite.

Also during the EVA, one of the EVA crew members became very cold and shut off water flow to his Liquid Cooling and Ventilation Garment. With the water flow turned off, the crew member’s Extravehicular Mobility Unit (EMU or spacesuit) helmet began to fog.

Prior to the EVA the lithium hydroxide canisters used during the previous EVA to scrub carbon dioxide from the EMU were inadvertently placed back into the EMUs instead of being changed for new canisters.

During the August 8th EVA, one of the Russian Orlan-D spacesuits used for the EVA experienced a cooling water pump failure. The crew member was able to overcome the failure by operating the primary and backup circulating fans simultaneously and occasionally resting. A physician later reported that the hands of both EVA crew members were injured.

During the April 11th EVA, one of the crew members experienced a minor urine containment anomaly, but the Liquid Cooling and Ventilation Garment (LCVG) absorbed most of the leakage. The crew member also noticed some helmet fogging. The fogging was due to adjustments made to the flow of cooling water to the LCVG when the crew member became too cold.

During the April 8th EVA, hardware configuration differences prevented the EVA crew member from capturing a satellite as planned. A grommet, which was on the satellite but did not appear in the blueprints, prevented the Trunnion Pin Attachment Device jaws from closing onto one of the satellite’s berthing docking pins. The failed attempts caused the satellite to lose sun-lock and begin to tumble. The EVA was forced to end early when readings indicated that the Manned Maneuvering Unit nitrogen propellant supply was low.

During the February 7th EVA, one of the quick-release pins (pip-pin) pulled free from the bracket used to secure the EVA slidewire, which allowed crew members to freely move in the payload bay while remaining safely tethered to the shuttle. The most probable cause of the pip-pin pulling free was an inadvertent pull on the push-pull type t-handle, possibly from an EVA tether, which would unlock the detent balls holding the pin in place and release it from the bracket.

During the July 30th EVA, the hand of a crew member testing an experimental wrench went numb. When using the tool, the crew member’s wrist was pressed against the suit wrist ring which caused the numbness.

During the flight of STS-96, the Simplified Aid for EVA Rescue (SAFER) NASA Standard Initiator (NSI) inadvertently fired sometime between May 27th and June 6th. The event likely happened either as crew members were egressing the airlock or after the EVA when removing the SAFER. The firing of the NSI resulted in the pyrotechnic isolation valve opening, causing a loss of gaseous nitrogen. Post-EVA checkouts were not part of the planned post-EVA operations, so the anomaly was not noticed until ground inspections occurred following the flight. The anomaly would have had minimal, if any, impact on the crew member’s ability to perform self-rescue during an EVA, because of the low observed leakage rate through the SAFER thrusters. If a worst-case leak rate happened on all thrusters before an EVA, a very low amount of gaseous nitrogen might have been left at the end of the EVA, which could have compromised the ability to perform self-rescue if required.

SAFER pyro failed to fire. Resulting lack of self-rescue led to redsesign.

A SAFER pyro failed to fire during the SAFER developmental test objective (DTO). The pyro valve failure was not discovered until a post-flight inspection of the SAFER hardware, since the DTO was performed with the crew member in a foot restraint. The failure triggered an investigation into the pyro and the redesign of the pyro system. Had this failure occurred during a self-rescue, the crew member would have been lost due to the latent design issue.

The November 29th EVA was terminated before the EVA crew members could leave the airlock. They were unable to unlatch the outer airlock hatch. Post-flight inspection determined that the failure was caused by a loose screw lodged within the hatch actuator mechanism gears.

The February 9th EVA was terminated early after the crew reported experiencing “level 3”cold (“unacceptably cold”) on a 1 to 8 scale created before launch.

After the EVA, when one crew member removed their helmet, the crew member noted an odor and suffered burning eyes. An air sample was taken, and the crew member washed their eyes with water. Post-flight analysis revealed no contaminants, and the most likely cause was contact with the anti-fogging soap solution.

During the December 5th EVA, one of the EVA crew members experienced difficulty receiving radio communications from Space Shuttle Endeavour and the ground. The other EVA crew member served as a relay, instead of the first crew member switching to a backup that would prevent downlinking of biomedical data to the ground.

The October 22nd EVA had to be terminated early when a problem occurred with the oxygen flow system of an EVA crew member’s Russian Orlan-DMA spacesuit. The suit had been worn 13 times and had exceeded its recommended operational lifespan. The suit was declared non-operational for further EVAs and was jettisoned out the airlock on a subsequent EVA.

The September 28th EVA had to be terminated early due to a failure of the cooling system of one of the Russian Orlan-DMA spacesuits. Ground control considered having the other EVA crew member complete the EVA alone, but decided against the idea.

During the June 25th EVA, while the EVA crew members were away from the payload bay and oriented toward space, they became cold enough to start shivering and experienced numbness and pain in their hands.

Also during the EVA, an untethered piece of Inertial Upper Stage tilt table equipment was almost lost, but was retrieved by one of the crew members.

During the April 19th EVA, telemetry from one of the Russian Orlan spacesuits indicated that the suit’s ventilation system was not functioning properly. Despite the anomaly the EVA was allowed to continue as planned, and all tasks were completed.

Heat exchanger of one Orlan suit failed to work, requiring use of umbilical for cooling. Umbilical limited translation range.

Crew member conducted portions of EVA alone.

At the beginning of the February 20th EVA, the heat exchanger of one Russian Orlan spacesuit clogged, forcing the crew member to remain near the Kvant 2 Special Airlock Compartment so that an umbilical from the Kvant 2 module heat exchanger could be attached to the suit. Because the umbilical was needed, the EVA crew member’s range of movement was limited, and the other EVA crew member had to conduct portions of the EVA alone.

Heat exchanger of one Orlan suit ran out of water, resulting in helmet fogging. Other cosmonaut guided crew member back.

Crew member had bruises on hands, elbows, and shoulders.

During the July 27th EVA the heat exchanger of one of the Russian Orlan spacesuits ran out of water. The lack of cooling water and the EVA workload resulted in that crew member’s helmet visor fogging from the increase in moisture in the suit. The affected crew member was guided back to the airlock by the other EVA crew member.

After the EVA, the crew members reported bruises on their hands, elbows, and shoulders.

During post-flight inspection it was discovered that the palm bar in the right hand glove worn by one crew member had shifted and punctured the restraint and glove bladder. It was determined that the palm bar was in an incorrect position due to insufficient restraints in the palm restraint tunnel allowing it to penetrate through a non-reinforced area of the palm restraint strap tunnel. To prevent recurrences of this anomaly, the palm bar strap was modified with stitching to prevent the bar from moving within the tunnel.

During the January 26th EVA, one of the crew members inadvertently kicked the Kurs docking antenna, knocking off one of the parabolic dishes. The issue was not discovered until a subsequent EVA on April 25th was conducted to determine why the visiting Progress M-7 failed to get a lock on the Kurs antenna.

At the beginning of the July 17th EVA, the EVA crew members inadvertently turned the airlock hatch handwheel farther than they were supposed to, violating the Kvant-2 airlock egress procedure and damaging the airlock. The normal procedure was to turn the handwheel until a 1-2 mm (0.04-0.08 in) gap opened around the lip of the hatch opening, allowing air to escape before the retaining hooks were released. Because the crew members turned the handwheel too far, the hooks released prematurely while there was still pressure in the airlock, causing the airlock to spring back against its hinges with 400 kg (880 lbs) of force. At the end of the EVA the crew members entered the airlock (after exceeding the 6-hr Russian Orlan-DMA suit safety limit) and discovered that they could not close the airlock

EMU camera and light detached from helmet, but held captive by electrical cable.

During the September 5th EVA, the Extravehicular Mobility Unit (EMU or spacesuit) camera and light detached from the EMU helmet. The camera and light were prevented from floating away by the electrical cable, mitigating a risk for collision with ISS.

During the July 22nd EVA, the crew members’ high metabolic rates exceeded the design limitations of the Extravehicular Mobility Unit (EMU or spacesuit) carbon dioxide scrubbing system, resulting in one of the EVA crew members experiencing elevated carbon dioxide levels. The EVA was terminated after only two of four new ISS batteries had been installed, leaving the ISS in a configuration with limited operational capability.

Tear in palm of EMU glove noticed when EVA was near completion. EVA terminated early.

Near the end of the May 17th EVA, a tear in the palm bar of one EVA crew member’s Extravehicular Mobility Unit (EMU or spacesuit) glove triggered an early termination. Because the termination happened during the cleanup phase of the EVA, there were no additional operational impacts.

EVs working close to rotating port Service Module solar array. Solar arrays should have been parked for EVA.

During the March 10th EVA, the EVA crew members were working close to the port side Service Module solar array. While translating past the array to the EVA worksite, NASA ground controllers noticed the array was still rotating. Per flight rules the solar arrays should have been in the parked position for the EVA to prevent inadvertent contact with the crew member. Russian flight control was notified, and the array was placed into the parked position prior to the EVA crew members moving past it again.

The November 20th EVA was terminated early after one of the EVA crew members experienced higher than acceptable levels of carbon dioxide. Once the crew member had returned to the airlock, the carbon dioxide returned to acceptable levels.

During the July 10th EVA, a planned jettison of the Soyuz thruster cover resulted in the cover colliding with one of the U.S. radiators. Because of the impact to the radiator, a survey was requested to check for damage. During the survey, damage was noted to the S1 radiator, but it was not determined if the damage came from the impact from the thruster cover.

After the October 30th EVA, one Extravehicular Mobility Unit (EMU or spacesuit) was deemed unusable due to a degraded sublimator. The sublimator water outlet temperature was higher than expected and had been trending upward on two prior EVAs. After the EVA the EMU was declared unusable for additional planned EVAs. Prior to the failure, the sublimator was used for STS-115 and STS-117 and had also shown high exit temperatures during those EVAs.

The August 15th EVA was terminated early per flight rules after a small hole was discovered in the Vectran layer of on crew member’s glove during a routine glove check between tasks. The cause of the glove damage was unable to be determined after an extensive review of the video from the EVA.

During the December 12th EVA, one crew member’s Simplified Aid for EVA Rescue (SAFER) Hand Controller Module (HCM) inadvertently deployed during airlock egress. The other EVA crew member re-stowed the HCM on the second attempt. The inadvertent deployment of the HCM caused the SAFER NASA Standard Initiator, or pyro, to accidently fire, which pressurized the SAFER thrusters and could have led to an inadvertent firing of the thrusters inside the airlock. The on-board spare SAFER was used for the subsequent EVAs. Flight rules were established after this flight for the crew to check the status of the SAFER after EVA if the HCM was inadvertently deployed.

V1’s SAFER left tower latch was bumped into the unlatched position, resulting in the left tower disengaging from the EMU. EVA was suspended until latch could be re-engaged by EV2.

During the July 10th EVA, left side upper latch of one crew member’s Simplified Aid for EVA Rescue (SAFER) came unlatched, resulting in it disengaging from the Extravehicular Mobility Unit (EMU or spacesuit). The EVA was suspended until the SAFER could be secured by the other crew member to prevent losing the SAFER unit. The unlatching was attributed to accidental contact with the latch in a tight working space, and Kapton tape was used on the subsequent EVA to make sure the SAFER latches remained closed.

During the August 3rd EVA, the ISS went into free drift while both of the crew members were conducting the EVA and no crew members remained inside. The three active Control Moment Gyroscopes (CMGs) that control the orientation of the ISS neared their saturation level. As a result the station entered free drift, resulting in a temporary loss of communications with mission control (S-band). Once the crew members had moved away from the area around the service module, the inhibited thrusters were re-enabled and fired to desaturate the CMGs.

EVA terminated early due to misconfigured valve depleting Orlan suit oxygen supply at start of EVA.

The June 24th EVA was cut short due to a primary oxygen tank pressure anomaly with one of the Russian Orlan-M spacesuits. The cause of the anomaly was traced to an open oxygen flow switch on the suit. The switch was not fully placed into the normal flow position, which caused an unexpected flow of oxygen into the suit and a depletion of the Orlan suit’s oxygen supply at the beginning of the EVA. Crew EVA procedures were updated to ensure the handle is in the proper position to prevent a future recurrence of this issue.

Temporary loss of ISS U.S. EVA capability due to EMU cooling loop contamination.

During pre-EVA checkout operations on May 19th, an anomaly occurred with the Extravehicular Mobility Unit (EMU or spacesuit) cooling loop. The cause of the failure was contamination in the cooling water, which caused the EMU water pump rotor to jam. The failure resulted in the loss of U.S. EVA capability aboard the ISS until November 2005. Analysis performed on hardware returned to the ground helped to develop a process to maintain the on-orbit system. The process involves using a filtration system before and after EVA operations to maintain the quality of the loop coolant and to clean the EMU coolant water before storage.

EV1 experienced eye irritation in both eyes. Attributed to leaking in-suit drink bag and anti-fog agent used in helmet.

During the April 24nd EVA, one of the EVA crew members experienced two instances of eye irritation similar to what was experienced on the prior EVA. The crew member observed that water escaped from the in-suit drink bag and was floating near the visor. The eye irritation was likely caused by water from the in-suit drink bag leaking and contacting the helmet visor and then the crew member’s eyes. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

EV1 experienced eye irritation in both eyes. Attributed to leaking in-suit drink bag and anti-fog agent used in helmet.

During the April 22nd EVA, one of the EVA crew members experienced an irritation in one eye and was told to perform a helmet purge to clear any particulates. The purge did not help the irritation, which eventually spread to both eyes. Approximately 30 minutes later the irritation began to subside due to natural eye tearing. The irritation was believed to have been caused by water from the in-suit drink bag leaking and contacting the helmet visor and then the crew member’s eyes. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

During the February 10th EVA, one of the EVA crew members was sprayed with ammonia from a leaking connector (quick disconnect). The EVA crew completed suit decontamination procedures prior to ingressing the airlock. These procedures consist of the crew members staying in the sun for a period of time, also known as a “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

Crew member experienced eye irritation, likely from anti-fog agent used in helmet.

During the December 3rd EVA, one of the EVA crew members coughed shortly after taking a sip of water. This caused liquid to bounce off the helmet visor, landing in the crew member’s right eye and causing a burning sensation. The crew member was instructed to ingress the airlock and purge the helmet to remedy the irritation. The cause of the eye irritation is believed to be the anti-fog agent used inside the helmet. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

During U.S. EVA 46 the SAFER was inadvertently activated. A SAFER checkout was performed after the EVA which confirmed that the pyro valve had fired during the EVA and resulted in the depletion of the nitrogen gas tanks. No rescue capability exists after depletion. In this case a crew member who inadvertently detached would have had no self-rescue capability.

One SCU failed during pre-breathe. Crew exposed to high temperatures during depress.

ISS Increment 51: During U.S. EVA 42 the ISS EMU Service and Cooling Umbilical (SCU) leaked during the EVA pre-breathe, causing a "softball sized" water bubble. Flight rules allow the crew member to go EVA with only one SCU available, but that means one crew member has to depressurize and repressurize without cooling and EVA duration may have to be shortened due to more time on battery power during depress. The crew reported almost unbearable temperatures during depress. In the event of an early EVA termination when no cold-soak time is available, crew members may be exposed to extreme temperatures during repress as well when only one SCU is available. The SCU was redesigned with strain relief to avoid future leaks and reduce the likelihood of one level of cooling capability being unavailable at the start of an EVA.

Helmet lights detached from helmet, but were held captive by the electrical cable.

During U.S. EVA 41, helmet lights detached from the helmet, but were held captive by the electrical cable. This is a recurrence of an event in September 2009. This failure could have impaired the crew member’s ability to perform nominal and emergency tasks, such as rapid emergency ingress during insolation.

During U.S. EVA 38, EV2’s right glove was used in a hammer-like motion to free a work light. Ground teams could not determine whether the glove had been internally damaged, so the gloves were restricted from further flight use (downgraded to class C) after the EVA.

The January 15th EVA was terminated early after water was observed in one EVA crew member’s helmet. The Extravehicular Mobility Unit (EMU or spacesuit) used for the EVA was the same one which had experienced previous water-in-helmet anomalies on EVAs 22 and 23. After this incident the EMU was declared unusable for future EVAs. Excessive water in the suit presents a hazard to the crew member’s vision, hearing, and breathing.

EMU feedwater switch inadvertently switched on prior to the airlock being at vacuum.

During depressurization for U.S. EVA 32, the feedwater switch of EMU 3010 was inadvertently switched on prior to the airlock being at vacuum. This allowed water to flow into the sublimator prior to the airlock environment reaching the triple point of water, which could have caused significant damage to the sublimator, resulting in loss of cooling capability and possible internal and external water leaks posing a hazard to the crew member. Subsequent failure or inability to quickly return to the airlock could lead to loss of crew. The EVA proceeded, but flight rules were subsequently updated to document that an inadvertent feedwater switch activation prior to 0.5 psia requires EVA termination.

During the December 24th EVA, the EVA crew members experienced difficulty disconnecting ammonia fluid lines and reported seeing ammonia flakes escaping a valve while disconnecting the lines. The quick-disconnect button on the valve could not be pushed, requiring the crew to use a tool called the Bail Control Tool, that had been developed after previous issues with quick disconnects. The crew successfully demated the quick disconnect, replaced the failed Pump Module, and completed the necessary suit decontamination procedures before entering the ISS. The decontamination procedures consist of the crew members staying in the sun for a period of time prior to ingressing the airlock, also known as a “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

After returning to the airlock, an EMU feedwater switch procedural error resulted in water flooding the sublimator rendering EMU no-go for EVA.

After returning to the airlock at the end of the December 21st EVA, one crew member accidentally actuated the Extravehicular Mobility Unit’s (EMU’s or spacesuit’s) Feedwater Switch for 2-3 seconds. Water flooded the sublimator, which can cause irreparable damage to the EMU, and the suit was declared unusable for EVA until proper drying procedures were performed.

1 to 1.5 liters of water entered the EMU ventilation loop and collected in the EMU helmet. EVA terminated early.

On July 16th about 44 minutes into the EVA, one crew member reported water in the helmet of the Extravehicular Mobility Unit (EMU or spacesuit). The EVA ground team and the crew member were unable to determine the source of the water. While the EVA continued, the amount of water in the helmet increased and eventually migrated from the back of the crew member’s head to his face. Approximately 1 to 1.5 liters of water had entered the EMU’s ventilation loop and collected in the EMU helmet. At this point the EVA was terminated and the crew member was able to find the way back to the airlock, despite the water obscuring his vision. All EVA crew members safely entered the airlock and re-pressurized.

During the July 9th EVA, one of the crew members noticed water in the Extravehicular Mobility Unit (EMU or spacesuit) helmet. At the time the water was incorrectly attributed to a leaking drink bag. This event was a precursor event to the anomaly on ISS EVA 23. Excessive water in the suit presents a hazard to the crew member’s vision, hearing, and breathing.

During the August 30th EVA, telemetry sent back to the ground controllers indicated that one of the Extravehicular Mobility Units (EMUs or spacesuits) was experiencing an unexpected cooling water temperature increase. Following the EVA the EMU suit was declared unusable for future EVAs and returned to Earth for investigation. The investigation determined that the cause of the temperature increase was a degradation in sublimator performance due to contamination from an unknown source.

During the May 25th EVA, one of the EVA crew members experienced eye irritation. The most probable cause was the helmet anti-fogging agent. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

Near the end of the May 20th EVA, one of the EVA crew members received the “Carbon Dioxide Sensor Bad” message. Because of the failure of the carbon dioxide sensor, the EVA was terminated early. The most likely cause of the failure was high humidity in the vent loop due to high oxygen use rates, along with the EVA taking place in a cool thermal environment. The sensor was dried out prior to the next EVA and functionality was restored.

During the August 11th EVA, one of the EVA crew members was exposed to ammonia from a leaking connector (quick disconnect) and experienced difficulty actuating the quick disconnect. The quick disconnect was eventually de-mated successfully, allowing for the subsequent removal and replacement of the failed coolant pump. Because the amount of leaking ammonia was small, the time required to finish the EVA allowed the ammonia to sublimate off the suit and decontamination procedures were not required at the end of the EVA.

During the August 7th EVA, one of the EVA crew members was exposed to ammonia from a leaking connector (quick disconnect) and experienced difficulty actuating the quick disconnect. The EVA crew completed suit decontamination procedures prior to ingressing the airlock. These procedures consist of the crew members staying in the sun for a period of time, also known as “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

During the February 14th EVA, one crew member was exposed to ammonia from a leaking connector (quick disconnect). The EVA crew completed suit decontamination procedures prior to ingressing the airlock. These procedures consist of the crew members staying in the sun for a period of time, also known as a “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

During the February 11th EVA, one of the EVA crew members noticed water in the Extravehicular Mobility Unit (EMU or spacesuit) helmet and in the EMU boots. Excessive water in the suit presents a hazard to the crew member’s vision, hearing, and breathing.

EVA is a commonly used acronym for Extravehicular Activity, which describes any activity for which a crew member must go outside the protected environment of the spacecraft. It is sometimes commonly referred to as "Spacewalking."

An “inadvertent release” is when an item (tool, fastener, bag, etc.), which should be restrained, becomes unintentionally freed and floats away.

MISSION ID

Gemini 4

Gemini 10

Salyut-7

STS-41B

STS-41C

STS-41G

STS-51A

STS-51L

Mir

STS-88/2A

STS-88/2A

STS-96/2A.1

STS-103/HST

STS-101/2A.2a

STS-92/3A

EVA

1

1

1

2

2

1

2

1

PE-13

1

2

1

3

1

3

# LOST

1

1

1

1

1

1

2

1

1

4

3

1

1

1

1

YEAR

1965

1966

1983

1984

1984

1984

1984

1985

1993

1998

1998

1999

1999

2000

2000

MISSION ID

STS-100/6A

STS-104/7A

STS-102/5A.1

ISS-4

ISS-11

ISS-12

ISS-13

STS-121/ULF1.1

STS-115/12A

STS-115/12A

STS-116/12A.1

STS-116/12A.1

ISS-14

ISS-15

STS-120/10A

EVA

2

3

1

RS 6

U.S. 13

U.S. 4

RS 16

3

1

2

1

3

RS 17A

RS 18

4

# LOST

1

1

2

1

1

1

1

1

1

1

1

1

3

1

2

YEAR

2001

2001

2002

2002

2005

2005

2006

2006

2006

2006

2006

2006

2007

2007

2007

MISSION ID

ISS-16

ISS-16

ISS-16

STS-124/1J

STS-126/ULF2

ISS-24

ISS-25

ISS-26

STS-133/ULF5

STS-134/ULF6

ISS-28

ISS-35

ISS-39

ISS-50

ISS-53

EVA

U.S. 11

U.S. 13

U.S. 14

2

1

RS 25

RS 26

RS 27

1

2

RS 29

RS 32

US 26

US 41

US 44

# LOST

1

4

1

1

1

4

1

1

1

4

1

1

2

1

1

YEAR

2007

2007

2008

2008

2008

2010

2010

2011

2011

2011

2011

2013

2014

2017

2017

Cumulative Hours as of 7/27/2016

U.S. - 1528

Russian - 689

China - 1

Total Hours by decade.

U.S., Russian, and Chinese

1960s

1960s

25

1970s

1970s

121

1980s

1980s

146

1990s

1990s

557

2000s

2000s

900

2010s

2010s

470

G4C | 6/3/1965-11/15/1966 | Gemini (4-6, 8-12)

The G4C suit was used by Ed White during the Gemini IV mission to perform the first U.S. spacewalk. The suit used a “combination of a pressure bladder and a link-net restraint” * to improve mobility over the previous Mercury suit when pressurized. The suit also provided thermal insulation and micrometeoroid protection. The suit relied on a 25-foot tether to supply oxygen from the spacecraft, communication, a medical telemetry link, and a mechanical attachment to the spacecraft. A sunvisor was attached to the helmet. The life support system was an open-loop design (breathing gas flowing into the suit and venting overboard). In addition to providing breathing oxygen for the crew member, the open-loop flow provided cooling and removed carbon dioxide and moisture. Cooling was controlled with a chest-mounted Ventilation Control Module. The suit operated at 3.7 psi.

The A7L was a custom-tailored spacesuit used for all the Apollo and Skylab spacewalks. It is sometimes called the “Moonsuit,” since it was used by everyone who walked on the moon to date. It was a “soft suit” since it did not rely on a rigid shell to retain its shape. Instead, various structural fabrics, straps, and cables maintained the shape while pressurized. Special joints at the ankles, knees, hips, shoulders, elbows, and wrists aided crew mobility. Later Apollo missions used the A7LB suit, which included neck and waist joints to allow the crew to operate the lunar rover. The suit was a closed-loop system that operated at a pressure of 3.7 psi and used a liquid cooling system for temperature control. When used on the moon and for other non-lunar Apollo EVAs, the suit included a backpack that contained the oxygen supply, carbon dioxide removal, batteries, cooling water, and radios. The Skylab-based EVAs did away with the backpack and used an umbilical.

The EMU was used for the Space Shuttle Program and is currently in use on the International Space Station. The semi-rigid design includes a hard upper torso with the helmet and primary life support system (PLSS) backpack attached to it. The flexible lower torso, arms, and legs use straps, cables, and pressure bearings to control ballooning and increase flexibility while pressurized. Unlike the early NASA spacesuits that were custom tailored for each crew member, the EMU uses interchangeable components and resizing mechanisms to allow use by various crew members. The suit is a closed-loop system operating at a pressure of 4.3 psi and uses a water sublimation system for cooling. The PLSS is designed to support the crew for up to eight hours. A secondary oxygen pack provides additional oxygen in case of an emergency.

The Berkut was used by Alexi Leonov to perform the world’s first spacewalk. Its design was based on the Vostok Sokol-1 suit, which had been used as a launch and entry suit to protect the crew members in case the capsule developed a leak. Modifications for use during spacewalks included the addition of a backpack life support system, a thermal protection layer on the outside, a sun visor on the helmet, and a safety tether to connect the suit to the capsule. The steel safety tether also provided backup oxygen, a mechanical load-relieving device, biomedical and suit telemetry, and a communication link with the capsule. The life support system was an open-loop design (breathing gas flowing into the suit and venting overboard) consisting of a backpack supplying 45 minutes of oxygen and a seven-meter umbilical that attached to backup supply of oxygen. In addition to providing breathing oxygen for the crew member, the open-loop flow provided cooling and removed carbon dioxide and moisture. The suit normally operated at a pressure of 5.88 psi, but could be reduced to 3.67 psi for contingency operations.

The Yastreb suit was developed based on the lessons learned from the first Russian EVA and was used for the second Russian EVA – a transfer by spacewalk of two crew members from Soyuz 4 to Soyuz 5. A system of built-in restraints was used to control the ballooning that was experienced with the Berkut suit. Another design change was to remove the life support pack from the back of the suit and instead affix it to either the chest or leg to make it easier for the crew to get in and out of the spacecraft. The suit relied on a steel safety tether, which also provided backup oxygen, a mechanical load-relieving device, biomedical and suit telemetry, and a communication link with the capsule. The life support system was an open-loop design (breathing gas flowing into the suit and venting overboard) consisting of a pack supplying 45 minutes of oxygen and a seven-meter umbilical that attached to a backup supply of oxygen. In addition to providing breathing oxygen for the crew member, the open-loop flow provided cooling and removed carbon dioxide and moisture. The suit normally operated at a pressure of 5.88 psi, but could be reduced to 3.67 psi for contingency operations.

The Orlan spacesuit replaced the Yastreb as the Soviet/Russian EVA spacesuit. The suit is a semi-rigid design (i.e., a hard upper torso with attached helmet and backpack). The suit simplifies donning by having the backpack double as a hatch. The flexible lower torso, arms, and legs use straps, cables, and pressure bearings to control ballooning and increase flexibility while pressurized. Where feasible, redundant pressure bladders, seals, and systems are used. The suit also differs from the Berkut and Yastreb suits in that it uses a closed-loop ventilation system and a liquid cooling system for thermal control. The initial design of the Orlan used a tether to supply oxygen, electrical power, and voice and data communications. Later models incorporated the oxygen supply, power (batteries), and radios (voice and data telemetry) into the suit to eliminate the need for the umbilical. In place of the umbilical, the crew uses safety tethers to connect the suit to the spacecraft or space station. The Orlan operates at a pressure of 5.8 psi.

The JSC SMA Flight Safety Office (FSO) created this graphic to highlight the risks of space exploration and to provide engineers with a summary of past experience. The chart depicts incidents during EVAs in orbit and on the lunar surface, which caused or could have caused injury, death, or the loss of the mission. Our goal is to encourage everyone to learn from the past to make present and future missions safer.

Incidents on the chart meet one or more of the following criteria:

Resulted in loss of life or could have resulted in loss of life under different conditions or circumstances (e.g., close calls, accidental crew detachment, water in helmet, EVA operations in thruster keep-out zone, failure to constrain/inhibit Ku Band operations…)

Resulted in injury or temporary incapacitation of a crew member, or otherwise compromised the crew member’s ability to perform critical tasks, such as self-rescue (e.g., frost bite, anti-fog agent in eyes).

During the March 18th 1965 EVA, the spacesuit the crew member was wearing while performing the EVA ballooned, causing an increase in the suit’s stiffness. After completing the EVA, the crew member entered the airlock head first and discovered that the suit would not bend enough to allow him to turn around and close the hatch. The crew member was forced to lower the pressure inside the suit, risking the potential onset of dysbarism (“the bends”). The struggle to enter and seal the airlock led to the crew member overheating, nearly to the point of heatstroke, due to the workload exceeding the cooling capacity of the early EVA suit.

After performing the EVA on August 15th, one of the crew members noticed a small puncture in the suit’s pressure bladder. The cause of the puncture was possibly a sharp wire on the KRT-10 antenna that the crew members removed from the Salyut 6 station.

On December 20th while performing an EVA from the Salyut 6 docking port, one crew member partially left the docking port without attaching the safety tether. While the crew member was untethered, the suit umbilical was still attached and prevented him from accidentally floating free of the station.

During the April 11th EVA, the Russian Orlan-DM spacesuit in use by one of the crew members experienced a minor pressure drop. The cause of the pressure drop was quickly determined to be an incorrect switch position, which was corrected, allowing the EVA to continue.

During the August 8th EVA, one of the Russian Orlan-D spacesuits used for the EVA experienced a cooling water pump failure. The crew member was able to overcome the failure by operating the primary and backup circulating fans simultaneously and occasionally resting. A physician later reported that the hands of both EVA crew members were injured.

During the July 30th EVA, the hand of a crew member testing an experimental wrench went numb. When using the tool, the crew member’s wrist was pressed against the suit wrist ring which caused the numbness.

The October 22nd EVA had to be terminated early when a problem occurred with the oxygen flow system of an EVA crew member’s Russian Orlan-DMA spacesuit. The suit had been worn 13 times and had exceeded its recommended operational lifespan. The suit was declared non-operational for further EVAs and was jettisoned out the airlock on a subsequent EVA.

The September 28th EVA had to be terminated early due to a failure of the cooling system of one of the Russian Orlan-DMA spacesuits. Ground control considered having the other EVA crew member complete the EVA alone, but decided against the idea.

During the April 19th EVA, telemetry from one of the Russian Orlan spacesuits indicated that the suit’s ventilation system was not functioning properly. Despite the anomaly the EVA was allowed to continue as planned, and all tasks were completed.

Heat exchanger of one Orlan suit failed to work, requiring use of umbilical for cooling. Umbilical limited translation range.

Crew member conducted portions of EVA alone.

At the beginning of the February 20th EVA, the heat exchanger of one Russian Orlan spacesuit clogged, forcing the crew member to remain near the Kvant 2 Special Airlock Compartment so that an umbilical from the Kvant 2 module heat exchanger could be attached to the suit. Because the umbilical was needed, the EVA crew member’s range of movement was limited, and the other EVA crew member had to conduct portions of the EVA alone.

Heat exchanger of one Orlan suit ran out of water, resulting in helmet fogging. Other cosmonaut guided crew member back.

Crew member had bruises on hands, elbows, and shoulders.

During the July 27th EVA the heat exchanger of one of the Russian Orlan spacesuits ran out of water. The lack of cooling water and the EVA workload resulted in that crew member’s helmet visor fogging from the increase in moisture in the suit. The affected crew member was guided back to the airlock by the other EVA crew member.

After the EVA, the crew members reported bruises on their hands, elbows, and shoulders.

During the January 26th EVA, one of the crew members inadvertently kicked the Kurs docking antenna, knocking off one of the parabolic dishes. The issue was not discovered until a subsequent EVA on April 25th was conducted to determine why the visiting Progress M-7 failed to get a lock on the Kurs antenna.

At the beginning of the July 17th EVA, the EVA crew members inadvertently turned the airlock hatch handwheel farther than they were supposed to, violating the Kvant-2 airlock egress procedure and damaging the airlock. The normal procedure was to turn the handwheel until a 1-2 mm (0.04-0.08 in) gap opened around the lip of the hatch opening, allowing air to escape before the retaining hooks were released. Because the crew members turned the handwheel too far, the hooks released prematurely while there was still pressure in the airlock, causing the airlock to spring back against its hinges with 400 kg (880 lbs) of force. At the end of the EVA the crew members entered the airlock (after exceeding the 6-hr Russian Orlan-DMA suit safety limit) and discovered that they could not close the airlock

EVs working close to rotating port Service Module solar array. Solar arrays should have been parked for EVA.

During the March 10th EVA, the EVA crew members were working close to the port side Service Module solar array. While translating past the array to the EVA worksite, NASA ground controllers noticed the array was still rotating. Per flight rules the solar arrays should have been in the parked position for the EVA to prevent inadvertent contact with the crew member. Russian flight control was notified, and the array was placed into the parked position prior to the EVA crew members moving past it again.

During the July 10th EVA, a planned jettison of the Soyuz thruster cover resulted in the cover colliding with one of the U.S. radiators. Because of the impact to the radiator, a survey was requested to check for damage. During the survey, damage was noted to the S1 radiator, but it was not determined if the damage came from the impact from the thruster cover.

During the August 3rd EVA, the ISS went into free drift while both of the crew members were conducting the EVA and no crew members remained inside. The three active Control Moment Gyroscopes (CMGs) that control the orientation of the ISS neared their saturation level. As a result the station entered free drift, resulting in a temporary loss of communications with mission control (S-band). Once the crew members had moved away from the area around the service module, the inhibited thrusters were re-enabled and fired to desaturate the CMGs.

EVA terminated early due to misconfigured valve depleting Orlan suit oxygen supply at start of EVA.

The June 24th EVA was cut short due to a primary oxygen tank pressure anomaly with one of the Russian Orlan-M spacesuits. The cause of the anomaly was traced to an open oxygen flow switch on the suit. The switch was not fully placed into the normal flow position, which caused an unexpected flow of oxygen into the suit and a depletion of the Orlan suit’s oxygen supply at the beginning of the EVA. Crew EVA procedures were updated to ensure the handle is in the proper position to prevent a future recurrence of this issue.

During the November 19th EVA, the crew members reported that the Extravehicular Mobility Unit’s (EMU or EVA suit) integrated thermal meteoroid garments were severely worn by the abrasive nature of the lunar dust. During the ascent to lunar orbit, the dust that was tracked into the Lunar Excursion Module became weightless, causing the crew members to experience difficulty breathing and requiring them to put on their helmets.

While egressing the Lunar Excursion Module (LEM), one of the crew members experienced difficulty crawling through the hatch due to tight clearances between the LEM hatch and the Portable Life Support System attached to the back of the suit.

During preparation for the September 13th EVA, the crew member that would be performing the spacewalk became overheated in the suit prior to egressing the capsule. Difficulty attaching the helmet visor contributed to the exertion and overheating. Because the life support oxygen cooling system heat exchanger could only operate in a vacuum, the crew member was not able to receive cooling from it. The EVA proceeded, but the crew member that remained in the capsule during the EVA brought the spacewalking crew member in early, noting that the crew member was sweating and not able to see well.

While moving over to the Agena docking target, the EVA crew member dislodged a sharp-edged electrical discharge ring that had the potential to damage the suit or its umbilical. After returning to the Gemini capsule, the EVA umbilical blocked one of the crew members from seeing the control panel, preventing the crew member from reporting the status of fuel to ground control. The difficulty that the crew members had with the umbilical also led to the radio accidentally being shut off for a brief time.

EVA terminated early due to eye irritations from lithium hydroxide being blown into helmet when suit fans were run simultaneously.

While executing the July 19th EVA, the crew member conducting the spacewalk experienced eye irritations causing the EVA to be terminated early. The cause of the irritation was traced to lithium hydroxide used for carbon dioxide absorption leaking into the helmet when both suit fans were operating simultaneously.

During the June 5th EVA, the crew member conducting the spacewalk experienced difficulty maneuvering around the outside of the capsule. While moving around during the EVA, the crew member’s suit became damaged, resulting in the crew member having thermal burns on his back from the sunlight striking the torn areas of the suit. The workload that the crew member experienced also exceeded the cooling capacity of the suit.

On June 3rd 1965 the crew of Gemini 4 experienced difficulty closing the capsule hatch after completion of the EVA. The crew was finally able to get the hatch closed when one crew member pulled on the other crew member while turning the hatch handle. While struggling to close the hatch, the crew member performing the spacewalk exerted himself beyond the cooling capacity of the suit, leading to slight fogging of the helmet visor.

While performing the February 3rd EVA, one crew member’s suit cooling system developed a leak similar to the one experienced on EVA 2. The crew member switched to minimum cooling, minimizing the amount of cooling water leaking, and completed the tasks assigned for the EVA. A later investigation determined that the probable cause of the leaking was due to the connectors being exposed to the cold environment of space and a small side load being placed on the connector.

During the December 29th EVA, a cooling water leak caused ice to form on the front of one crew member’s suit. A later investigation determined that the probable cause of the leaking was due to the connectors being exposed to the cold environment of space and a small side load being placed on the connector.

During the December 25th EVA, a cooling water leak caused yellow ice to form on the front of one crew member’s belly-mounted pressure control unit. The color of the ice indicated that the leak was from one of the two water connectors (quick disconnects) of the composite connector at the interface of the life support umbilical/pressure control unit. The leak was too small to fully deplete the cooling water supply. A spare unit was used on subsequent EVAs. A later investigation determined that the probable cause of the leaking was due to the connectors being exposed to the cold environment of space and a small side load being placed on the connector.

During the November 22nd EVA, the crew members experienced difficulty keeping their suit umbilicals separated. This cost them time and effort to keep the umbilicals under control and could have presented a risk of severe entanglement.

During the September 22nd EVA, the airlock module suit cooling system suffered leaks and was inoperable for the EVA. The physically undemanding nature of the tasks to be completed allowed the EVA to proceed with only air cooling.

Primary EVA heat exchanger module suffered minor clogging during the EVA, leading engineers to design a new module to serve as a backup.

During the June 7th EVA, the Skylab primary EVA heat exchanger module suffered from minor clogging, but the EVA was able to continue. The clogging of the heat exchanger led engineers to design a new module that would serve as a backup. The new backup module was delivered to Skylab in July 1973 by the next crew.

One LRV fender broke off, which resulted in the crew getting showered by dust while driving.

During the December 11th EVA, one of the crew members suffered contusions to his hand while extracting a core sample. The device used to obtain the core samples became stuck, despite a design that was supposed to ease removal of the core sample. During the EVA, part of the Lunar Rover fender was broken off, but taped back in position. On the way to the first geological survey station the “repaired” fender fell off and showered the crew members with dust.

During the EVA on April 23rd, the Lunar Rover suffered a temporary navigational computer failure. The crew members used the sun’s position to determine their location, allowing them to locate the Lunar Excursion Module. An investigation later revealed that the most probable cause of the issues with the navigation system was improper wire crimps on the flight vehicle when compared with the solder connections used in the test vehicle on the ground. The improper crimps allowed the wires to loosen when exposed to cold temperatures, causing loose connections.

During the EVA on April 22nd one crew member’s Portable Life Support System radio antenna struck the Lunar Excursion Module’s hatch frame, breaking off a portion of the antenna. The damage to the antenna caused a small drop in signal strength, but the EVA was allowed to continue.

During the April 21st EVA, one of the crew members tripped over the heat flow sensor cable connected to the Apollo Lunar Surface Experiments Package (ALSEP), tearing it loose. Mission control elected not to repair the cable on the subsequent EVA due to concern that the repair would take too much time and could possibly short-circuit the ALSEP.

One of the crew members attempted to jump and salute the flag they had placed, but slipped and fell onto the Portable Life Support System (PLSS). However, no significant damage was done to the PLSS, which remained operational.

After ingressing the Lunar Excursion Module, the crew members reported the same problems that previous flights had with the lunar dust – stuck zippers and disconnects, and scratched indicators that were difficult to read.

During the August 1st EVA, the vertical Portable Life Support System (PLSS) radio antenna snapped off of one crew member’s PLSS. The other crew member taped it back into a horizontal position. While navigating back to the Lunar Excursion Module (LEM), the crew members experienced difficulty navigating until they encountered their outbound tracks, which led them back to the LEM. An investigation later revealed that the most probable cause of the issues with the navigation system was improper wire crimps on the flight vehicle when compared with the solder connections used in the test vehicle on the ground. The improper crimps allowed the wires to loosen when exposed to cold temperatures, causing loose connections.

During the July 31st EVA, while driving the Lunar Roving Vehicle, the front steering failed. The crew member driving was able to steer the rover with only the rear steering. Also during the EVA, one of the crew members’ drink bags failed to operate, causing the crew member to become dehydrated. After completing the EVA, the crew members discovered that the abrasive lunar dust made the Portable Life Support System (PLSS) connectors tight and difficult to operate. In addition, the crew members also experienced pain in their fingers caused by their fingernails pressing against their glove fingertips.

Difficulty in handling satellite due to lack of visual cues between EVA astronauts.

Accidentally reused lithium hydroxide canisters from first EVA.

During the September 1st EVA when the EVA crew members were handling a satellite from opposite sides, a lack of sight between them hindered visual cues and posed a potential threat of collision with Space Shuttle Discovery. The lack of visual cues caused the EVA crew members to impart opposite motions into the satellite.

Also during the EVA, one of the EVA crew members became very cold and shut off water flow to his Liquid Cooling and Ventilation Garment. With the water flow turned off, the crew member’s Extravehicular Mobility Unit (EMU or spacesuit) helmet began to fog.

Prior to the EVA the lithium hydroxide canisters used during the previous EVA to scrub carbon dioxide from the EMU were inadvertently placed back into the EMUs instead of being changed for new canisters.

During the April 11th EVA, one of the crew members experienced a minor urine containment anomaly, but the Liquid Cooling and Ventilation Garment (LCVG) absorbed most of the leakage. The crew member also noticed some helmet fogging. The fogging was due to adjustments made to the flow of cooling water to the LCVG when the crew member became too cold.

During the April 8th EVA, hardware configuration differences prevented the EVA crew member from capturing a satellite as planned. A grommet, which was on the satellite but did not appear in the blueprints, prevented the Trunnion Pin Attachment Device jaws from closing onto one of the satellite’s berthing docking pins. The failed attempts caused the satellite to lose sun-lock and begin to tumble. The EVA was forced to end early when readings indicated that the Manned Maneuvering Unit nitrogen propellant supply was low.

During the February 7th EVA, one of the quick-release pins (pip-pin) pulled free from the bracket used to secure the EVA slidewire, which allowed crew members to freely move in the payload bay while remaining safely tethered to the shuttle. The most probable cause of the pip-pin pulling free was an inadvertent pull on the push-pull type t-handle, possibly from an EVA tether, which would unlock the detent balls holding the pin in place and release it from the bracket.

During the flight of STS-96, the Simplified Aid for EVA Rescue (SAFER) NASA Standard Initiator (NSI) inadvertently fired sometime between May 27th and June 6th. The event likely happened either as crew members were egressing the airlock or after the EVA when removing the SAFER. The firing of the NSI resulted in the pyrotechnic isolation valve opening, causing a loss of gaseous nitrogen. Post-EVA checkouts were not part of the planned post-EVA operations, so the anomaly was not noticed until ground inspections occurred following the flight. The anomaly would have had minimal, if any, impact on the crew member’s ability to perform self-rescue during an EVA, because of the low observed leakage rate through the SAFER thrusters. If a worst-case leak rate happened on all thrusters before an EVA, a very low amount of gaseous nitrogen might have been left at the end of the EVA, which could have compromised the ability to perform self-rescue if required.

SAFER pyro failed to fire. Resulting lack of self-rescue led to redsesign.

A SAFER pyro failed to fire during the SAFER developmental test objective (DTO). The pyro valve failure was not discovered until a post-flight inspection of the SAFER hardware, since the DTO was performed with the crew member in a foot restraint. The failure triggered an investigation into the pyro and the redesign of the pyro system. Had this failure occurred during a self-rescue, the crew member would have been lost due to the latent design issue.

The November 29th EVA was terminated before the EVA crew members could leave the airlock. They were unable to unlatch the outer airlock hatch. Post-flight inspection determined that the failure was caused by a loose screw lodged within the hatch actuator mechanism gears.

The February 9th EVA was terminated early after the crew reported experiencing “level 3”cold (“unacceptably cold”) on a 1 to 8 scale created before launch.

After the EVA, when one crew member removed their helmet, the crew member noted an odor and suffered burning eyes. An air sample was taken, and the crew member washed their eyes with water. Post-flight analysis revealed no contaminants, and the most likely cause was contact with the anti-fogging soap solution.

During the December 5th EVA, one of the EVA crew members experienced difficulty receiving radio communications from Space Shuttle Endeavour and the ground. The other EVA crew member served as a relay, instead of the first crew member switching to a backup that would prevent downlinking of biomedical data to the ground.

During the June 25th EVA, while the EVA crew members were away from the payload bay and oriented toward space, they became cold enough to start shivering and experienced numbness and pain in their hands.

Also during the EVA, an untethered piece of Inertial Upper Stage tilt table equipment was almost lost, but was retrieved by one of the crew members.

During post-flight inspection it was discovered that the palm bar in the right hand glove worn by one crew member had shifted and punctured the restraint and glove bladder. It was determined that the palm bar was in an incorrect position due to insufficient restraints in the palm restraint tunnel allowing it to penetrate through a non-reinforced area of the palm restraint strap tunnel. To prevent recurrences of this anomaly, the palm bar strap was modified with stitching to prevent the bar from moving within the tunnel.

EMU camera and light detached from helmet, but held captive by electrical cable.

During the September 5th EVA, the Extravehicular Mobility Unit (EMU or spacesuit) camera and light detached from the EMU helmet. The camera and light were prevented from floating away by the electrical cable, mitigating a risk for collision with ISS.

During the July 22nd EVA, the crew members’ high metabolic rates exceeded the design limitations of the Extravehicular Mobility Unit (EMU or spacesuit) carbon dioxide scrubbing system, resulting in one of the EVA crew members experiencing elevated carbon dioxide levels. The EVA was terminated after only two of four new ISS batteries had been installed, leaving the ISS in a configuration with limited operational capability.

Tear in palm of EMU glove noticed when EVA was near completion. EVA terminated early.

Near the end of the May 17th EVA, a tear in the palm bar of one EVA crew member’s Extravehicular Mobility Unit (EMU or spacesuit) glove triggered an early termination. Because the termination happened during the cleanup phase of the EVA, there were no additional operational impacts.

The November 20th EVA was terminated early after one of the EVA crew members experienced higher than acceptable levels of carbon dioxide. Once the crew member had returned to the airlock, the carbon dioxide returned to acceptable levels.

After the October 30th EVA, one Extravehicular Mobility Unit (EMU or spacesuit) was deemed unusable due to a degraded sublimator. The sublimator water outlet temperature was higher than expected and had been trending upward on two prior EVAs. After the EVA the EMU was declared unusable for additional planned EVAs. Prior to the failure, the sublimator was used for STS-115 and STS-117 and had also shown high exit temperatures during those EVAs.

The August 15th EVA was terminated early per flight rules after a small hole was discovered in the Vectran layer of on crew member’s glove during a routine glove check between tasks. The cause of the glove damage was unable to be determined after an extensive review of the video from the EVA.

During the December 12th EVA, one crew member’s Simplified Aid for EVA Rescue (SAFER) Hand Controller Module (HCM) inadvertently deployed during airlock egress. The other EVA crew member re-stowed the HCM on the second attempt. The inadvertent deployment of the HCM caused the SAFER NASA Standard Initiator, or pyro, to accidently fire, which pressurized the SAFER thrusters and could have led to an inadvertent firing of the thrusters inside the airlock. The on-board spare SAFER was used for the subsequent EVAs. Flight rules were established after this flight for the crew to check the status of the SAFER after EVA if the HCM was inadvertently deployed.

V1’s SAFER left tower latch was bumped into the unlatched position, resulting in the left tower disengaging from the EMU. EVA was suspended until latch could be re-engaged by EV2.

During the July 10th EVA, left side upper latch of one crew member’s Simplified Aid for EVA Rescue (SAFER) came unlatched, resulting in it disengaging from the Extravehicular Mobility Unit (EMU or spacesuit). The EVA was suspended until the SAFER could be secured by the other crew member to prevent losing the SAFER unit. The unlatching was attributed to accidental contact with the latch in a tight working space, and Kapton tape was used on the subsequent EVA to make sure the SAFER latches remained closed.

Temporary loss of ISS U.S. EVA capability due to EMU cooling loop contamination.

During pre-EVA checkout operations on May 19th, an anomaly occurred with the Extravehicular Mobility Unit (EMU or spacesuit) cooling loop. The cause of the failure was contamination in the cooling water, which caused the EMU water pump rotor to jam. The failure resulted in the loss of U.S. EVA capability aboard the ISS until November 2005. Analysis performed on hardware returned to the ground helped to develop a process to maintain the on-orbit system. The process involves using a filtration system before and after EVA operations to maintain the quality of the loop coolant and to clean the EMU coolant water before storage.

EV1 experienced eye irritation in both eyes. Attributed to leaking in-suit drink bag and anti-fog agent used in helmet.

During the April 24nd EVA, one of the EVA crew members experienced two instances of eye irritation similar to what was experienced on the prior EVA. The crew member observed that water escaped from the in-suit drink bag and was floating near the visor. The eye irritation was likely caused by water from the in-suit drink bag leaking and contacting the helmet visor and then the crew member’s eyes. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

EV1 experienced eye irritation in both eyes. Attributed to leaking in-suit drink bag and anti-fog agent used in helmet.

During the April 22nd EVA, one of the EVA crew members experienced an irritation in one eye and was told to perform a helmet purge to clear any particulates. The purge did not help the irritation, which eventually spread to both eyes. Approximately 30 minutes later the irritation began to subside due to natural eye tearing. The irritation was believed to have been caused by water from the in-suit drink bag leaking and contacting the helmet visor and then the crew member’s eyes. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

During the February 10th EVA, one of the EVA crew members was sprayed with ammonia from a leaking connector (quick disconnect). The EVA crew completed suit decontamination procedures prior to ingressing the airlock. These procedures consist of the crew members staying in the sun for a period of time, also known as a “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

Crew member experienced eye irritation, likely from anti-fog agent used in helmet.

During the December 3rd EVA, one of the EVA crew members coughed shortly after taking a sip of water. This caused liquid to bounce off the helmet visor, landing in the crew member’s right eye and causing a burning sensation. The crew member was instructed to ingress the airlock and purge the helmet to remedy the irritation. The cause of the eye irritation is believed to be the anti-fog agent used inside the helmet. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

During U.S. EVA 46 the SAFER was inadvertently activated. A SAFER checkout was performed after the EVA which confirmed that the pyro valve had fired during the EVA and resulted in the depletion of the nitrogen gas tanks. No rescue capability exists after depletion. In this case a crew member who inadvertently detached would have had no self-rescue capability.

One SCU failed during pre-breathe. Crew exposed to high temperatures during depress.

ISS Increment 51: During U.S. EVA 42 the ISS EMU Service and Cooling Umbilical (SCU) leaked during the EVA pre-breathe, causing a "softball sized" water bubble. Flight rules allow the crew member to go EVA with only one SCU available, but that means one crew member has to depressurize and repressurize without cooling and EVA duration may have to be shortened due to more time on battery power during depress. The crew reported almost unbearable temperatures during depress. In the event of an early EVA termination when no cold-soak time is available, crew members may be exposed to extreme temperatures during repress as well when only one SCU is available. The SCU was redesigned with strain relief to avoid future leaks and reduce the likelihood of one level of cooling capability being unavailable at the start of an EVA.

Helmet lights detached from helmet, but were held captive by the electrical cable.

During U.S. EVA 41, helmet lights detached from the helmet, but were held captive by the electrical cable. This is a recurrence of an event in September 2009. This failure could have impaired the crew member’s ability to perform nominal and emergency tasks, such as rapid emergency ingress during insolation.

During U.S. EVA 38, EV2’s right glove was used in a hammer-like motion to free a work light. Ground teams could not determine whether the glove had been internally damaged, so the gloves were restricted from further flight use (downgraded to class C) after the EVA.

The January 15th EVA was terminated early after water was observed in one EVA crew member’s helmet. The Extravehicular Mobility Unit (EMU or spacesuit) used for the EVA was the same one which had experienced previous water-in-helmet anomalies on EVAs 22 and 23. After this incident the EMU was declared unusable for future EVAs. Excessive water in the suit presents a hazard to the crew member’s vision, hearing, and breathing.

EMU feedwater switch inadvertently switched on prior to the airlock being at vacuum.

During depressurization for U.S. EVA 32, the feedwater switch of EMU 3010 was inadvertently switched on prior to the airlock being at vacuum. This allowed water to flow into the sublimator prior to the airlock environment reaching the triple point of water, which could have caused significant damage to the sublimator, resulting in loss of cooling capability and possible internal and external water leaks posing a hazard to the crew member. Subsequent failure or inability to quickly return to the airlock could lead to loss of crew. The EVA proceeded, but flight rules were subsequently updated to document that an inadvertent feedwater switch activation prior to 0.5 psia requires EVA termination.

During the December 24th EVA, the EVA crew members experienced difficulty disconnecting ammonia fluid lines and reported seeing ammonia flakes escaping a valve while disconnecting the lines. The quick-disconnect button on the valve could not be pushed, requiring the crew to use a tool called the Bail Control Tool, that had been developed after previous issues with quick disconnects. The crew successfully demated the quick disconnect, replaced the failed Pump Module, and completed the necessary suit decontamination procedures before entering the ISS. The decontamination procedures consist of the crew members staying in the sun for a period of time prior to ingressing the airlock, also known as a “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

After returning to the airlock, an EMU feedwater switch procedural error resulted in water flooding the sublimator rendering EMU no-go for EVA.

After returning to the airlock at the end of the December 21st EVA, one crew member accidentally actuated the Extravehicular Mobility Unit’s (EMU’s or spacesuit’s) Feedwater Switch for 2-3 seconds. Water flooded the sublimator, which can cause irreparable damage to the EMU, and the suit was declared unusable for EVA until proper drying procedures were performed.

1 to 1.5 liters of water entered the EMU ventilation loop and collected in the EMU helmet. EVA terminated early.

On July 16th about 44 minutes into the EVA, one crew member reported water in the helmet of the Extravehicular Mobility Unit (EMU or spacesuit). The EVA ground team and the crew member were unable to determine the source of the water. While the EVA continued, the amount of water in the helmet increased and eventually migrated from the back of the crew member’s head to his face. Approximately 1 to 1.5 liters of water had entered the EMU’s ventilation loop and collected in the EMU helmet. At this point the EVA was terminated and the crew member was able to find the way back to the airlock, despite the water obscuring his vision. All EVA crew members safely entered the airlock and re-pressurized.

During the August 30th EVA, telemetry sent back to the ground controllers indicated that one of the Extravehicular Mobility Units (EMUs or spacesuits) was experiencing an unexpected cooling water temperature increase. Following the EVA the EMU suit was declared unusable for future EVAs and returned to Earth for investigation. The investigation determined that the cause of the temperature increase was a degradation in sublimator performance due to contamination from an unknown source.

During the August 30th EVA, telemetry sent back to the ground controllers indicated that one of the Extravehicular Mobility Units (EMUs or spacesuits) was experiencing an unexpected cooling water temperature increase. Following the EVA the EMU suit was declared unusable for future EVAs and returned to Earth for investigation. The investigation determined that the cause of the temperature increase was a degradation in sublimator performance due to contamination from an unknown source.

During the May 25th EVA, one of the EVA crew members experienced eye irritation. The most probable cause was the helmet anti-fogging agent. Irritation to the crew member’s eyes during an EVA can causing tearing, resulting in the tears collecting around the eyes and impairing vision.

Near the end of the May 20th EVA, one of the EVA crew members received the “Carbon Dioxide Sensor Bad” message. Because of the failure of the carbon dioxide sensor, the EVA was terminated early. The most likely cause of the failure was high humidity in the vent loop due to high oxygen use rates, along with the EVA taking place in a cool thermal environment. The sensor was dried out prior to the next EVA and functionality was restored.

During the August 11th EVA, one of the EVA crew members was exposed to ammonia from a leaking connector (quick disconnect) and experienced difficulty actuating the quick disconnect. The quick disconnect was eventually de-mated successfully, allowing for the subsequent removal and replacement of the failed coolant pump. Because the amount of leaking ammonia was small, the time required to finish the EVA allowed the ammonia to sublimate off the suit and decontamination procedures were not required at the end of the EVA.

During the August 7th EVA, one of the EVA crew members was exposed to ammonia from a leaking connector (quick disconnect) and experienced difficulty actuating the quick disconnect. The EVA crew completed suit decontamination procedures prior to ingressing the airlock. These procedures consist of the crew members staying in the sun for a period of time, also known as “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

During the February 14th EVA, one crew member was exposed to ammonia from a leaking connector (quick disconnect). The EVA crew completed suit decontamination procedures prior to ingressing the airlock. These procedures consist of the crew members staying in the sun for a period of time, also known as a “bakeout.” The ammonia used in the ISS External Thermal Control System poses a serious health risk (eye/throat irritation, inflammation of the respiratory tract, or death) if allowed to enter the ISS habitable area.

During the February 11th EVA, one of the EVA crew members noticed water in the Extravehicular Mobility Unit (EMU or spacesuit) helmet and in the EMU boots. Excessive water in the suit presents a hazard to the crew member’s vision, hearing, and breathing.